-LRB- CNN -RRB- -- Kurt Haskell 's eyes were locked on the seatback monitor in front of him when the words of a passing flight attendant caught his attention .

`` She said something smells like smoke , '' recalled Haskell , a passenger on Northwest Airlines Flight 253 . `` I got out of my seat and took a few steps up the aisle , and that 's when Row 19 burst into flames . ''

Two passengers quickly hauled the man sitting in the burning row into the first-class section . A flight attendant grabbed a fire extinguisher and put out the flames in what became the latest example of citizens taking action when counterterrorism safeguards fall short .

At the time , Haskell said he did n't know if he was witnessing a terrorist attack or a freak accident . In the hours ahead , he and the other passengers learned the details of the near-tragedy .

The suspect , later identified as Umar Farouk AbdulMutallab , allegedly tried to bring down the airliner with explosives concealed in his underwear . Despite warnings that he allegedly was consorting with Islamist extremists and that he was listed in a database of suspicious people , the 23-year-old Nigerian was allowed to board the plane .

`` We dodged a bullet but just barely , '' President Obama said last week . A disaster was averted by `` brave individuals -- not because the system worked , '' he said .

Brave individuals also were credited for saving the 197 people on American Airlines Flight 63 in December 2001 . Passengers and crew saw Richard Reid trying to ignite a bomb in his shoe . The bomb malfunctioned , and those onboard subdued him and tied him to his seat .

Three months before , on September 11 , passengers overtook hijackers on United Airlines Flight 93 , foiling an apparent attempt to crash the plane into a Washington target . The plane instead crashed in a Pennsylvania field , killing everyone aboard .

In situations such as these , everyday people play `` the most vital role '' in the nation 's fight against terrorism , said Bruce Hoffman , a terrorism expert at Georgetown University .

`` Citizens have a role and they have a responsibility , but it 's the last and it 's the thinnest line of defense , '' Hoffman said .

On the front end , the counterterrorism system could n't function without help from the public , Hoffman said , pointing to the United Kingdom 's campaign against the Irish Republican Army and Israel 's against the second Intifada .

Signs on subways told people to be vigilant and to report any suspicious behavior or bags left behind . In both cases , `` citizen tips were absolutely essential , '' Hoffman said .

While the threat of attacks on U.S. soil pales in comparison to the Britain of the late 20th century or modern-day Israel , the United States still needs its citizens to remain alert so as to thwart terrorist attempts to establish a local base .

`` More than anything else , it 's an attitude that we need to have that we ca n't leave everything to the government to fix , '' Hoffman said .

Temple University psychologist Frank Farley said everyday heroism is empowering for the whole culture and helps combat the `` it 's not my job '' mentality .

`` What does it mean , everyday heroism ? It means something you can do where you are , with what you 've got , '' Farley said , echoing the words of Theodore Roosevelt .

However , Farley , who has studied heroism for more than four decades , cautioned that overstating the threat or scaring people could counteract the public 's willingness to act courageously .

In his initial remarks after the attempted Christmas Day attack , Obama called on Americans to remain `` vigilant , but also be confident . ''

`` This incident , like several that have preceded it , demonstrates that an alert and courageous citizenry are far more resilient than an isolated extremist , '' he said .

Robert Heibel , a retired FBI agent who was the deputy chief of counterterrorism in the 1980s , said education can better equip the public as the nation combats terrorism . Homeland security officials need to tell people what to look for and what 's suspicious .

`` We live in a world where our antennas need to be up , '' said Heibel , who heads the Institute for Intelligence Studies at Mercyhurst College in Erie , Pennsylvania . But he added that `` we do n't want to turn America into a vigilante society . ''

The public needs to understand who the terrorists are and how to counter arguments made by Islamic extremists , he said .

`` Terrorism is not going to go away , but I think how we view this opponent , how we view the radical Islamists , has got to change , '' Heibel said . `` We have to be able to sell ourselves better than we do . We are working against ourselves in many areas . ''

Hoffman added that as officials work to educate the public , they face a challenging pursuit as well .

`` There is a very thin line between prudence and paranoia , '' he said . `` Striking that balance is enormously important . I think that 's also where our leaders and where government has a very important role to make sure we always stay on the right side of that balance . ''

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Passengers , crew helped subdue suspect on botched Christmas Day terror attack

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In such situations , citizens are the last and the thinnest line of defense , terrorism expert says

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`` Everyday heroism '' combats mentality of leaving safety to pros , psychologist says

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Education can better equip the public as the nation fights terrorism , retired FBI agent says